What causes atrial arrhythmias?

Many causes: First off, need an ultrasound (echo) of your heart, because structural abnormalites of the heart are the first big cause that needs to be eliminated. If your heart is structurally normal, then the other big cause for atrial arrhythmias is diet and drugs -- especially any caffeine or diet pills. Finally, sometimes it is just idiopathic -- which means we cannot find a cause.